Updated: 2026-10-16
Quick answer: Your custody or support order decides the medical expense split, and most states divide a child’s uninsured costs (co-pays, deductibles, prescriptions, braces, therapy) in proportion to each parent’s income, on top of base child support. One parent is usually ordered to carry the child’s health insurance. The parent who pays a bill sends the other an itemized request with proof, and the other parent reimburses their share within the deadline in the order. In California, that means billing within 90 days and paying within 30 days if the order sets no other deadline.
Disclaimer: This article is general information drawn from state statutes, federal law, and IRS publications. It is not legal or tax advice. Medical support rules differ by state and by the wording of your order, so check with a family law attorney, your local child support agency, or a tax professional about your situation.
The orthodontist quotes $5,800. Insurance covers $1,500. One parent books the consultation, pays the deposit, and texts a photo of the invoice three months later. The other parent says they were never asked. This is the most common money fight between co-parents, and almost all of it comes down to three questions: who carries the insurance, how the uninsured part is split, and how fast the other parent has to pay.
This guide covers the medical expense split in custody cases: the state rules for uninsured costs, who has to provide coverage, how reimbursement works, and what to do when a parent won’t pay. For the full list of shared costs beyond health care, see our co-parenting shared expenses list.
Table of Contents
- How are medical expenses split in a custody case?
- What do state laws say about uninsured medical costs?
- Who has to provide the child’s health insurance?
- What is a National Medical Support Notice?
- What counts as an uninsured medical expense?
- How do you ask the other parent to reimburse you?
- What if the other parent won’t pay their share?
- Can both parents use an HSA or deduct the child’s medical bills?
- What should your order say about medical expenses?
- Frequently Asked Questions
How are medical expenses split in a custody case?
Your order decides. A custody order, a child support order, or a divorce decree almost always contains a medical support section, and the split written there controls, whatever your parenting schedule looks like.
Medical costs sit outside base child support. Base support covers ordinary recurring costs like food and housing. A child’s health costs are too irregular to fold into a monthly number, so courts handle them in two separate pieces:
- Insurance. One parent is ordered to cover the child, and the premium cost is often shared or credited in the support calculation.
- Uninsured costs. What insurance doesn’t pay is split between the parents as additional support, usually by percentage.
The percentage is usually based on income, not time. A 50/50 parenting schedule does not mean a 50/50 medical split. If one parent earns 60% of the parents’ combined income, that parent typically pays 60% of the uninsured orthodontist bill. Some orders set a flat split instead, often 50/50. Read the number in your order and use it. Our guide to how child support is calculated explains where the income shares come from.
What do state laws say about uninsured medical costs?
Each state sets a default rule that applies when the order doesn’t say otherwise. Here is how four large states handle it, taken from their statutes.
| State | Uninsured costs split | Key rule |
|---|---|---|
| TX | As the court allocates | Counts as child support |
| CA | By net income share | Bill in 90 days, pay in 30 |
| FL | By income share | Added to support, or set % |
| WA | Same % as base support | Covers braces, therapy |
Texas. Under Texas Family Code § 154.183, the court allocates “the reasonable and necessary health care expenses, including vision and dental expenses,” that insurance doesn’t reimburse, plus deductibles and co-payments, “between the parties, according to their circumstances.” The same section makes court-ordered medical and dental support “a child support obligation” that can be enforced by any child support remedy, including wage withholding.
California. Since September 1, 2024, Family Code § 4062 requires the court to order “the reasonable uninsured health care costs for the children” as additional child support. Section 4061 divides those costs “in proportion to the parents’ net incomes” unless a parent asks for a different split or the court orders one. Older California guides that say the split is automatically 50/50 describe the rule before that change.
Florida. Under Florida Statutes § 61.30(8), health insurance costs and “any noncovered medical, dental, and prescription medication expenses of the child” are added to the basic support obligation “unless these expenses have been ordered to be separately paid on a percentage basis.” Either way, each parent’s share follows their percentage of combined net income.
Washington. RCW 26.19.080 says health care costs “are not included in the economic table” and “shall be shared by the parents in the same proportion as the basic child support obligation.” The statute lists medical, dental, orthodontia, vision, chiropractic, mental health treatment, and prescriptions.
Other states follow one of these patterns. Our child support by state guide links to each state’s rules.
Who has to provide the child’s health insurance?
Usually the parent who can get coverage through work at a reasonable cost. Courts look at cost and access first, then decide who covers the child.
Texas spells out the order of priority. Under Texas Family Code § 154.182, if insurance is available through a parent’s job at a reasonable cost, the court orders that parent to add the child. If not, it may order coverage from another source. If neither works, the court orders the paying parent to pay cash medical support of up to 9% of their annual resources. Section 154.181(e) defines “reasonable cost” for health insurance as no more than 9% of the paying parent’s annual resources. For dental coverage, § 154.1815 sets the line at 1.5%. When the parent who receives support is the one carrying the child’s insurance, the court adds the child’s share of the premium to the support amount, again capped at reasonable cost.
California focuses on using the ordered plan. Under Family Code § 4063(e) and (f), the court-ordered coverage is the one to use “at all times,” including the plan’s preferred providers. A parent who buys extra coverage, or who takes the child out of network when the plan doesn’t allow it, pays the extra cost alone. When a parent challenges the plan in court, the judge presumes it is accessible if care is available within 50 miles of the child’s home (§ 4063(g)).
That rule matters in real life. If one parent prefers a specialist outside the plan, that preference may become their bill alone unless the other parent agrees in writing or the court finds the plan can’t meet the child’s needs.
What is a National Medical Support Notice?
A National Medical Support Notice (NMSN) is a federal form that tells an employer to enroll a child in a parent’s workplace health plan. If you received one at work, a state child support agency sent it because a support order requires you to provide health coverage.
Under 42 U.S.C. § 666(a)(19), every child support order enforced by a state child support agency must include medical support. When the parent required to provide coverage has a known employer, the agency uses the NMSN to tell the employer. The employer then has 20 business days to pass it to the health plan. For newly hired parents, the agency sends the notice within two days of the new-hire report, along with the income withholding notice. If the parent’s job ends, the employer must tell the agency.
Section 666 ties the notice to the federal rules for workplace health plans. The U.S. Department of Labor publishes a guide to qualified medical child support orders, the orders that require a plan to cover a parent’s child, which covers how plan administrators handle them. If the notice is wrong, for example because the child already has coverage the order accepts, contact the agency named on it quickly, since the employer must act within its deadline.
What counts as an uninsured medical expense?
Anything health-related for the child that insurance doesn’t fully pay, as long as it is reasonable and necessary. The common items:
- Co-pays and deductibles
- Prescriptions and the uncovered part of medications
- Orthodontia and dental work
- Glasses, contacts, and eye exams
- Counseling and mental health treatment
- Physical therapy and chiropractic care
- Emergency care
Washington’s statute names most of these. Texas includes vision and dental expenses plus deductibles and co-payments. California adds a useful presumption: under § 4063(d), costs actually paid for a child’s uninsured health care are presumed reasonable, so the parent who objects has to show why the cost was not.
The disputes are usually about elective care and about asking first. Cosmetic procedures, a second opinion out of network, or a private therapist chosen without discussion are where parents disagree. Many orders deal with this by requiring notice or consent before a non-emergency expense over a set amount. Emergencies are almost always exempt.
How do you ask the other parent to reimburse you?
Send one itemized request in writing with proof of payment, and give the deadline. California writes the process into law, and it works as a model anywhere.
Under California Family Code § 4063(b):
- The parent who incurs or pays a cost sends the other parent an itemized statement “within a reasonable time, but not more than 90 days after accruing the costs.”
- If you paid the whole bill, include proof of payment and ask for the other parent’s court-ordered share.
- If you paid only your share, include proof and ask the other parent to pay the rest directly to the provider, with the payment details.
- The other parent pays within the period in the order. If the order doesn’t set one, they pay “within a reasonable time not to exceed 30 days” from notice, or on the provider’s payment schedule.
- A parent who disputes the request pays first, then asks the court for relief.
The fifth point surprises people. In California, the parent who disagrees with a bill is expected to pay it and then go to court, not hold the money back.
What to include in every request:
- The date of service, the provider, and what the care was for
- The explanation of benefits from the insurer showing the uninsured amount
- The receipt or statement showing what you paid
- The share you’re asking for, the percentage from the order, and the due date
Send it through one channel you both use, such as a co-parenting app or email, so there’s a dated record. Our co-parenting log template helps you keep that record.
What if the other parent won’t pay their share?
Start with one clear demand, then use the enforcement route your state allows. In some states unpaid medical support is treated exactly like unpaid child support.
| Situation | What you can do |
|---|---|
| TX order | Enforce as child support, incl. wage withholding |
| CA order | Motion to enforce; fees possible |
| Any order | Contempt motion if the term is specific |
| IV-D case | Ask the support agency to act |
In Texas, § 154.183 makes court-ordered medical support “a child support obligation” that “may be enforced by any means available for the enforcement of child support, including withholding from earnings.” In California, § 4063(c) lets either parent file a noticed motion to enforce, and the court may award filing costs and reasonable attorney’s fees against a parent who “acted without reasonable cause.”
Elsewhere, an unpaid share is a violation of the order like any other, and the usual tool is a contempt motion. That works best when the order sets a clear percentage and deadline. Our guides on contempt of court in custody cases and filing a motion for contempt cover the process.
One rule holds everywhere: keep paying your own support while the dispute runs. Holding back child support because a medical bill went unpaid turns their violation into yours, as our guide to not paying child support explains.
Can both parents use an HSA or deduct the child’s medical bills?
Often, yes. For medical purposes, the IRS treats a child of divorced or separated parents as a dependent of both parents, even though only one parent can claim the child for other tax benefits.
IRS Publication 502 says a child of divorced or separated parents “can be treated as a dependent of both parents” for the medical and dental expense deduction. Each parent can include the medical expenses they pay if the child is in the custody of one or both parents for more than half the year, the parents provide more than half the child’s support, and the parents are divorced, legally separated, separated under a written agreement, or living apart for the last six months of the year. The deduction applies only to medical expenses above 7.5% of adjusted gross income and only if you itemize, so many parents won’t benefit.
Health savings accounts follow the same idea. IRS Publication 969 says that for HSA purposes, such a child “is treated as the dependent of both parents whether or not the custodial parent releases the claim to the child’s exemption.” Either parent can use their own HSA for the child’s qualified medical costs. Don’t claim the same expense twice: a bill paid tax-free from an HSA can’t also be deducted. Check the details with a tax professional before you file. Our guide to co-parenting and taxes covers filing status, the child tax credit, and which parent claims the child.
What should your order say about medical expenses?
Specific numbers and deadlines. Vague language like “the parties shall share reasonable medical expenses” is hard to enforce, because a court has to find a clear duty that was broken. These are examples of the kind of terms parents and attorneys write into agreements, not language from any statute:
- Coverage. “Father shall maintain health and dental insurance for the child through his employer as long as it is available at reasonable cost, and shall give Mother the insurance cards and plan information within 10 days.”
- The split. “Uninsured medical, dental, vision, orthodontic, counseling, and prescription costs shall be paid 60% by Father and 40% by Mother.”
- Notice. “Except in an emergency, a parent shall notify the other in writing before incurring a non-emergency uninsured expense over $300.”
- Deadlines. “A parent seeking reimbursement shall send the itemized statement and proof of payment within 30 days of payment, and the other parent shall pay their share within 30 days of receipt.”
- Providers. “The parents shall use in-network providers unless both agree in writing or the care is an emergency.”
If your current order lacks these terms, you can add them through an agreed modification. If a new insurance premium or a change in income also moves the support amount, our guide to child support modification explains when and how to ask for a recalculation. Our guides to modifying a parenting plan and the parenting plan template explain how, and child support explained covers how the support order itself can change.
Frequently Asked Questions
Who pays medical bills in joint custody?
The custody or support order decides, not the custody label. Most states split the child’s uninsured costs by each parent’s share of combined income, so in joint custody the higher earner usually pays a larger share. Some orders set a flat 50/50 split instead.
Is medical support part of child support?
It is paid in addition to base child support, but many states treat it as child support for enforcement. Texas Family Code § 154.183 calls court-ordered medical and dental support “a child support obligation” that can be collected through wage withholding.
How long do I have to ask for reimbursement of medical expenses?
Check your order first. In California, Family Code § 4063 requires the itemized statement within 90 days of the cost, and the other parent must pay within 30 days of notice if the order sets no other deadline. Other states rely on the deadline in the order.
Can my ex refuse to pay for a doctor they didn’t agree to?
Possibly, for non-emergency care. Many orders require notice or agreement before a large elective expense, and California makes the parent who uses an out-of-network provider pay the extra cost alone. Emergency care is generally shared regardless.
Why did I get a National Medical Support Notice?
A state child support agency sent it to your employer because a support order requires you to provide health coverage for your child. Federal law gives the employer 20 business days to forward it to the health plan, which then enrolls the child.
